Buggy code:
public class SourceAnnotationHandler implements MetadataProcessor < TypeElement , Element > { private final ProcessingEnvironment processingEnv ; private final Types typeUtility ; private final CompileTimeLogger logger ; protected SourceAnnotationHandler . AccessFilter propertyAccessFilter = new SourceAnnotationHandler . AccessFilter ( PROPERTY ) ; protected SourceAnnotationHandler . AccessFilter fieldAccessFilter = new SourceAnnotationHandler . AccessFilter ( FIELD ) ; protected SourceAnnotationHandler . KindFilter fieldFilter = new SourceAnnotationHandler . KindFilter ( ElementKind . FIELD ) ; protected SourceAnnotationHandler . KindFilter methodFilter = new SourceAnnotationHandler . KindFilter ( ElementKind . METHOD ) ; protected SourceAnnotationHandler . TransientFilter nonTransientFilter = new SourceAnnotationHandler . TransientFilter ( ) ; protected SourceAnnotationHandler . AnnotatedFilter annotatedFilter = new SourceAnnotationHandler . AnnotatedFilter ( ) ; protected SourceAnnotationHandler . GetterFilter getterFilter = new SourceAnnotationHandler . GetterFilter ( ) ; protected SourceAnnotationHandler . SetterFilter setterFilter = new SourceAnnotationHandler . SetterFilter ( ) ; protected static List < Class < ? extends Annotation > > mappingAnnos = new ArrayList < Class < ? extends Annotation > > ( ) ; private static Localizer _loc = Localizer . forPackage ( SourceAnnotationHandler . class ) ; public SourceAnnotationHandler ( ProcessingEnvironment processingEnv , CompileTimeLogger logger ) { } public int determineTypeAccess ( TypeElement type ) { } public int determineMemberAccess ( Element m ) { } public List < Exception > validateAccess ( TypeElement t ) { } public boolean isMixedAccess ( TypeElement t ) { } public Set < Element > getPersistentMembers ( TypeElement type ) { } private Set < Element > getFieldAccessPersistentMembers ( TypeElement type ) { } private Set < Element > getPropertyAccessPersistentMembers ( TypeElement type ) { } private Set < Element > getDefaultAccessPersistentMembers ( TypeElement type , int access ) { } private int getImplicitAccessType ( TypeElement type ) { } Set < Element > merge ( Set < ? extends Element > a , Set < ? extends Element > b ) { } private Set < ExecutableElement > matchGetterAndSetter ( Set < ExecutableElement > getters , Set < ExecutableElement > setters ) { } private static interface InclusiveFilter < T extends Element > { boolean includes ( T e ) { } } < T extends Element > Set < T > filter ( Collection < T > coll , SourceAnnotationHandler . InclusiveFilter ... filters ) { } static class GetterFilter implements SourceAnnotationHandler . InclusiveFilter < ExecutableElement > { public boolean includes ( ExecutableElement method ) { } } static class SetterFilter implements SourceAnnotationHandler . InclusiveFilter < ExecutableElement > { public boolean includes ( ExecutableElement method ) { } } static class AccessFilter implements SourceAnnotationHandler . InclusiveFilter < Element > { final AccessType target ; public AccessFilter ( AccessType target ) { } public boolean includes ( Element obj ) { } } static class KindFilter implements SourceAnnotationHandler . InclusiveFilter < Element > { final ElementKind target ; public KindFilter ( ElementKind target ) { } public boolean includes ( Element obj ) { } } static class TransientFilter implements SourceAnnotationHandler . InclusiveFilter < Element > { public boolean includes ( Element obj ) { } } static class AnnotatedFilter implements SourceAnnotationHandler . InclusiveFilter < Element > { public boolean includes ( Element obj ) { } } AccessType getExplicitAccessType ( TypeElement type ) { } public static Object getAnnotationValue ( Element decl , Class < ? extends Annotation > anno ) { } public static Object getAnnotationValue ( Element e , Class < ? extends Annotation > anno , String attr ) { } public static String toString ( Collection < ? extends Element > elements ) { } String toDetails ( Element e ) { TypeMirror mirror = e . asType ( ) ; <START_BUG> return new StringBuffer ( e . getKind ( ) . toString ( ) ) . append ( "<seq2seq4repair_space>" ) . append ( e . toString ( ) ) . append ( "Mirror<seq2seq4repair_space>" ) . append ( mirror . getKind ( ) . toString ( ) ) . append ( mirror . toString ( ) ) . toString ( ) ; <END_BUG> } String getPersistentMemberName ( Element e ) { } public String extractFieldName ( ExecutableElement method ) { } public static boolean isAnnotated ( Element e ) { } boolean isAnnotatedAsEntity ( Element e ) { } public static boolean isAnnotatedWith ( Element e , Class < ? extends Annotation > anno ) { } public static boolean isAnnotatedWith ( Element e , Set < String > annos ) { } TypeMirror getTargetEntityType ( Element e ) { } String getDeclaredTypeName ( TypeMirror mirror ) { } String getDeclaredTypeName ( TypeMirror mirror , boolean box ) { } TypeMirror getDeclaredType ( Element e ) { } private boolean isPrimitive ( TypeMirror mirror ) { } public TypeMirror box ( TypeMirror t ) { } TypeMirror getTypeParameter ( Element e , TypeMirror mirror , int index , boolean checkTarget ) { } public TypeElement getPersistentSupertype ( TypeElement cls ) { } public static boolean isBoolean ( TypeMirror type ) { } public static boolean isVoid ( TypeMirror type ) { } public static boolean isMethod ( Element e ) { } public static boolean isNormalGetter ( ExecutableElement method ) { } public static boolean isBooleanGetter ( ExecutableElement method ) { } public static boolean isGetter ( ExecutableElement method ) { } public static boolean isSetter ( ExecutableElement method ) { } public static boolean isRootObject ( TypeMirror type ) { } public static boolean startsWith ( String full , String head ) { } public static boolean equalsByValue ( Enum < ? > e , Object v ) { } }

Fix:
return new StringBuilder ( e . getKind ( ) . toString ( ) ) . append ( "<seq2seq4repair_space>" ) . append ( e . toString ( ) ) . append ( "Mirror<seq2seq4repair_space>" ) . append ( mirror . getKind ( ) . toString ( ) ) . append ( mirror . toString ( ) ) . toString ( ) ;